list of most expensive mtg cards Gaming: The five from The Dark The 10 Most Expensive Magic:

Players can respond to a spell that will give you your tenth permanent, but they can't respond to you getting the city's blessing once you control that tenth permanent

It is an interesting card with a unique effect, and it is actually very powerful right now, given the presence of the Elemental Incarnations or cards like Archon of Cruelty or Urzas Saga Tokens

This can beat up players itself pretty well, but it also works well with a wider board by allowing you to keep up some defenses after an attack with a bunch of vigilance creatures

Overall, I wouldnt overload on these anti-lifegain cards as if you feel like you need to, then you probably shouldnt be playing a red deck in that metagame

If the target creature is an illegal target as Hydaelyn, the Mothercrystal's last ability tries to resolve, it won't resolve and none of its effects will happen